Effects of hook shape and cement replacement materials on pullout behaviour of steel fibres

The purpose of this study is to investigate the effect of hook shape and material of high tensile strength hooked end steel fibres and the impact of cement replacement materials on pullout behaviour of steel fibres from cementitious composites. The cement replacements which have been used in this research included silica fume, pulverised fuel ash, limestone filler and ground granulated blast-furnace slag. In total, more than 800 samples have been manufactured for experimental research on compressive strength and pullout behaviour of hooked end steel fibres from cementitious matrices. The effects of parameters such as water/binder ratio, cement replacement content, age of sample, hooked end shape and tensile strength of fibre on fibre–matrix pullout behaviour were determined. The results of tests and analysis indicate that hook shape, tensile strength of fibre and silica fume affect the maximum pullout force and ground granulated blast-furnace slag can significantly improve the residual pullout energy which would be useful for the optimisation of steel fibre reinforced concrete. The outcome of this research may be useful to widen the potential applications of the material across civil engineering.